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Search Results: 1 - 10 of 4469 matches for " Weber Porto "
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Generation of arbitrarily two-point correlated random networks
Sebastian Weber,Markus Porto
Physics , 2007, DOI: 10.1103/PhysRevE.76.046111
Abstract: Random networks are intensively used as null models to investigate properties of complex networks. We describe an efficient and accurate algorithm to generate arbitrarily two-point correlated undirected random networks without self- or multiple-edges among vertices. With the goal to systematically investigate the influence of two-point correlations, we furthermore develop a formalism to construct a joint degree distribution $P(j,k)$ which allows to fix an arbitrary degree distribution $P(k)$ and an arbitrary average nearest neighbor function $\knn(k)$ simultaneously. Using the presented algorithm, this formalism is demonstrated with scale-free networks ($P(k) \propto k^{-\gamma}$) and empirical complex networks ($P(k)$ taken from network) as examples. Finally, we generalize our algorithm to annealed networks which allows networks to be represented in a mean-field like manner.
Multicomponent reaction-diffusion processes on complex networks
Sebastian Weber,Markus Porto
Physics , 2006, DOI: 10.1103/PhysRevE.74.046108
Abstract: We study the reaction-diffusion process $A + B \to \emptyset$ on uncorrelated scale-free networks analytically. By a mean-field ansatz we derive analytical expressions for the particle pair-correlations and the particle density. Expressing the time evolution of the particle density in terms of the instantaneous particle pair-correlations, we determine analytically the `jamming' effect which arises in the case of multicomponent, pair-wise reactions. Comparing the relevant terms within the differential equation for the particle density, we find that the `jamming' effect diminishes in the long-time, low-density limit. This even holds true for the hubs of the network, despite that the hubs dynamically attract the particles.
Generating random networks with given degree-degree correlations and degree-dependent clustering
Andreas Pusch,Sebastian Weber,Markus Porto
Physics , 2007, DOI: 10.1103/PhysRevE.77.017101
Abstract: Random networks are widely used to model complex networks and research their properties. In order to get a good approximation of complex networks encountered in various disciplines of science, the ability to tune various statistical properties of random networks is very important. In this manuscript we present an algorithm which is able to construct arbitrarily degree-degree correlated networks with adjustable degree-dependent clustering. We verify the algorithm by using empirical networks as input and describe additionally a simple way to fix a degree-dependent clustering function if degree-degree correlations are given.
Chemistry Based on Renewable Raw Materials: Perspectives for a Sugar Cane-Based Biorefinery
Murillo Villela Filho,Carlos Araujo,Alfredo Bonfá,Weber Porto
Enzyme Research , 2011, DOI: 10.4061/2011/654596
Abstract: Carbohydrates are nowadays a very competitive feedstock for the chemical industry because their availability is compatible with world-scale chemical production and their price, based on the carbon content, is comparable to that of petrochemicals. At the same time, demand is rising for biobased products. Brazilian sugar cane is a competitive feedstock source that is opening the door to a wide range of bio-based products. This essay begins with the importance of the feedstock for the chemical industry and discusses developments in sugar cane processing that lead to low cost feedstocks. Thus, sugar cane enables a new chemical industry, as it delivers a competitive raw material and a source of energy. As a result, sugar mills are being transformed into sustainable biorefineries that fully exploit the potential of sugar cane. 1. Introduction In a market economy, corporations aim to maximize profit. Governments or society in general impose constraints on and regulate the maximization of profit. Product quality, operational safety, and respect for the environment all have to be fulfilled. To maximize profit, the chemical industry always seeks the most competitive feedstock. When competitive feedstock is available, opportunities for new processes and technologies arise. Technology for converting carbon dioxide into a feedstock source has been developed and used in Brazil since the inception of Pro-álcool, the Brazilian national alcohol program, in the 1970s [1]. Given the legislation, the market demand for sustainable products, and the progress being made in biotechnology and catalysis, developers are working on new processes, which are giving rise to a wide range of biobased products. The old sugar mills (engenhos) have become efficient industrial facilities (usinas) that produce sweeteners, ethanol, and bioenergy. Recent developments involve transforming sugar mills into biorefineries. Besides sweeteners, biofuel, and bioenergy, the biorefineries will be able to produce bioplastics and other chemicals by using the whole cane via alcohol chemistry and fermentative routes. This essay analyzes the industry’s historical response to new developments stemming from the rise of competitive feedstock and the opportunities that it creates. It focuses on sugar cane, its availability as a feedstock source, and the technologies that can turn sugar cane into an important starting point for chemistry of the future. Based on recent examples of processes and market developments, a new arrangement of integrated agroindustry, processing sugar cane and yielding higher value
Early cephalometric characteristics in Class III malocclusion
Farias, Vanessa Costa;Tesch, Ricardo de Souza;Denardin, Odilon Victor Porto;Ursi, Weber;
Dental Press Journal of Orthodontics , 2012, DOI: 10.1590/S2176-94512012000200011
Abstract: objective: early identification of craniofacial morphological characteristics allows orthopedic segmented interventions to attenuate dentoskeletal discrepancies, which may be partially disguised by natural dental compensation. to investigate the morphological characteristics of brazilian children with class iii malocclusion, in stages i and ii of cervical vertebrae maturation and compare them with the characteristics of class i control patients. methods: pre-orthodontic treatment records of 20 patients with class iii malocclusion and 20 control class i patients, matched by the same skeletal maturity index and sex, were selected. the craniofacial structures and their relationships were divided into different categories for analysis. angular and linear measures were adopted from the analyses previously described by downs, jarabak, jacobson and mcnamara. the differences found between the groups of class iii patients and class i control group, both subdivided according to the stage of cervical vertebrae maturation (i or ii), were assessed by analysis of variance (anova), complemented by bonferroni's multiple mean comparisons test. results: the analysis of variance showed statistically significant differences in the different studied groups, between the mean values found for some angular (sna, snb, anb) and linear variables (co - gn, n - perp pog, go - me, wits, s - go, ar - go). conclusion: assessed children displaying class iii malocclusion show normal anterior base of skull and maxilla, and anterior positioning of the mandible partially related to increased posterior facial height with consequent mandibular counterclockwise rotation.
Bases epidemiológicas para análise das más oclus?es morfológicas como fatores de risco no desenvolvimento das desordens temporomandibulares de origem articular
Tesch, Ricardo de Souza;Ursi, Weber José da Silva;Denardin, Odilon Victor Porto;
Revista Dental Press de Ortodontia e Ortopedia Facial , 2004, DOI: 10.1590/S1415-54192004000500006
Abstract: among the researches undertaken in epidemiology, a peculiar group of pathologies present either unknown or not totally understood origins. temporomandibular disorders (tmd) can be classified in this subgroup. three basic observational strategies have been used to approach the etiologic role of malocclusion in tmd development, inside the epidemiological repertoire. they are sectional, case-control and cohort studies. some clinical trials are conducted based on the removal of the suspect etiologic factor. based on the literature reviewed in terms of the methodology applied in the selected studies, we can infer that: the definition of possible etiological factors related to specific sub-groups of tmd is primordial not to underestimate the role of malocclusion in the development of this kind of disorders; the characterization of a normal occlusion like the one associated with the lower risk for tmd problems development can be useful, but the application of these parameters will probably result inappropriate for the resolution of a joint problem which is already established; the concept of lower risk occlusion would involve a small slide discrepancy between rcp and icp, small incisal overlap, positive overbite and no posterior crossbite. this concept is similar to the concept of normal occlusion supported for decades, although a deviation from the normal criterion instead of an absolute criterion must be tolerated; although it may be prudent to establish therapeutic morphologic goals that seek what is observed in untreated occlusions deemed normal or ideal, the establishment of an occlusion that reach all these gnathologic criteria, by means of orthodontic treatment, might be either impossible or probably unnecessary.
Nódulos de tireóide: valor da ultra-sonografia e da biópsia por pun o aspirativa no diagnóstico de cancer
Peccin Simone,Furlanetto Tania Weber,Castro José Augusto Sisson de,Furtado álvaro Porto Alegre
Revista da Associa??o Médica Brasileira , 2003,
Abstract: Os nódulos de tireóide s o um problema clínico comum e a pun o aspirativa por agulha fina (PAAF) é o principal exame utilizado para seu diagnóstico diferencial. Recentemente, foi demonstrado que algumas características ultra-sonográficas dos nódulos est o associadas a um maior risco de cancer. Entretanto, n o encontramos estudos que avaliassem o desempenho dos dois exames de forma comparativa e/ou complementar. OBJETIVO: Avaliar o desempenho da ultra-sonografia (US), da PAAF e de sua combina o no diagnóstico de cancer em nódulos de tireóide. MéTODOS: Oitenta pacientes com nódulos únicos ou dominantes, com indica o cirúrgica, foram selecionados dentre 289 pacientes com nódulos tireoidianos atendidos entre mar o de 1995 e julho de 1997. Os pacientes foram submetidos à PAAF e à US de tireóide por um dos autores. A PAAF foi considerada positiva quando os achados citológicos eram suspeitos ou diagnósticos de cancer. A US foi considerada positiva quando os nódulos apresentavam pelo menos um dos seguintes achados: microcalcifica es, hipoecogenicidade ou halo ausente. PAAF e US foram combinados em paralelo (o resultado positivo em qualquer um dos dois exames era considerado indicativo de malignidade) e em série (somente o resultado positivo de ambos os testes indicava presen a de malignidade). RESULTADOS: A sensibilidade e a especificidade da PAAF na detec o do cancer em nódulos de tireóide foram, respectivamente, 87% e 62%, e a sensibilidade e a especificidade da US foram, respectivamente, 81% e 70%. A combina o em série dos dois exames (PAAF e US) resultou em sensibilidade de 69% e especificidade de 91%, e a combina o em paralelo (PAAF ou US) apresentou sensibilidade de 94% e especificidade de 52%. CONCLUS O: A US pode ser útil na avalia o dos nódulos de tireóide, alternativamente ou em combina es com a PAAF. Como o resultado da US depende da experiência do operador e das características do equipamento, s o necessários estudos em diferentes centros para o seu uso na prática clínica.
A importancia dos eventos científicos na forma o acadêmica: estudantes de biblioteconomia
Aureliana Lopes de Lacerda,Claudiane Weber,Marchelly Pereira Porto,Romário Antunes da Silva
Revista ACB , 2008,
Abstract: [Portuguese]Investiga a importancia dos eventos científicos na forma o acadêmica dos estudantes do curso de gradua o em Biblioteconomia. Avalia a participa o dos estudantes em eventos científicos e observa se há estímulo no decorrer de suas atividades acadêmicas para que ocorra esta participa o. Considera que os eventos científicos criam a possibilidade de intera o entre os estudantes e os profissionais da área e favorece o acesso a novas informa es. A amostra é composta por estudantes dos cursos de Biblioteconomia da Universidade Federal de Santa Catarina - UFSC e da Universidade Estadual de Santa Catarina - UDESC. Os resultados apontam que os eventos científicos podem auxiliar no desenvolvimento da forma o acadêmica dos estudantes. [English]nvestigates the importance of scientific meeting on academic life for Library Science students. Evaluates the students participation on meetings and observes if are incentive to participate on these activities to this participation occurs. It considers that scientific events create the possibility of interaction between students and the professionals of this area and favors the access to new information. Are utilized as sample, for the developement of the research, students from Library Science course in Universidade Federal de Santa Catarina - UFSC and from Universidade Estadual de Santa Catarina - UDESC. It shows that scientific events can aid the delopement of the academic formation of the studens.
Possíveis fatores etiológicos para desordens temporomandibulares de origem articular com implica??es para diagnóstico e tratamento
Maydana, Aline Vettore;Tesch, Ricardo de Souza;Denardin, Odilon Vitor Porto;Ursi, Weber José da Silva;Dworkin, Samuel Franklin;
Dental Press Journal of Orthodontics , 2010, DOI: 10.1590/S2176-94512010000300010
Abstract: the authors reviewed the factors involved in the etiology, diagnosis and treatment of temporomandibular joint disorders (tmd). although essential, specific criteria for inclusion and exclusion in tmd diagnosis have shown limited usefulness. currently, the research diagnostic criteria for temporomandibular disorders (rdc/tmd) offer the best evidence-based classification for the most common tmd subgroups. the rdc/tmd includes not only methods for physical diagnostic classification, comprised in axis i, but also methods to assess the intensity and severity of chronic pain and the levels of non-specific depressive and physical symptoms, in axis ii. although historically malocclusions have been identified as risk factors for the development of tmd-including those predominantly joint-related-in many cases the association established between these variables seems to have taken opposite directions. regarding internal tmj derangements, the results of studies on the induced shortening of the mandibular ramus, secondary to anterior articular disk displacement, indicate that repositioning the displaced disk in children or young adolescents may make more sense than previously imagined. the therapeutic use of dietary supplements, such as glucosamine sulfate, seems to be a safe alternative to the anti-inflammatory drugs commonly used to control pain associated with tmj osteoarthritis, although evidence of its effectiveness for most tmd patients has yet to be fully established.
Nódulos de tireóide: valor da ultra-sonografia e da biópsia por pun??o aspirativa no diagnóstico de cancer
Peccin, Simone;Furlanetto, Tania Weber;Castro, José Augusto Sisson de;Furtado, álvaro Porto Alegre;Brasil, Beatriz Assis;Czepielewski, Mauro Ant?nio;
Revista da Associa??o Médica Brasileira , 2003, DOI: 10.1590/S0104-42302003000200031
Abstract: background: thyroid nodules are a very common clinical problem and fine-needle aspiration biopsy (fnab) is its main diagnostic test. recently, it has been shown that some ultrasonographic features are associated to an increased risk of cancer, but a comparison between fnab and ultrasonography (us) or its combination is not available. the aim of this study was to evaluate fnab and us performance, isolated or combined, for cancer diagnosis in thyroid nodules. methods: eighty patients, with palpable solitary thyroid nodules or multinodular goiters, who were to undergo surgery, were selected among 289 patients seen in our clinic between march, 1995 and july, 1997. us and fnab were performed by one of us. us was considered positive for cancer when microcalcifications, absent halo or hypoechogenicity were seen. fnab was considered positive for cancer when it was either suspicious or compatible with malignancy. both methods (fnab and us) were evaluated in parallel combination (positive when fnab or us was positive) and in serial combination (positive when both, fnab and us, were positive). results: sensitivity and specificity of fnab and us for cancer diagnosis in thyroid nodules were, respectively, 87% and 62%, and 81% and 70%. serial combination of fna and us had sensitivity of 69% and specificity of 91%, and parallel combination resulted in sensitivity of 94% and specificity of 52%. conclusion: the us had good accuracy in the evaluation of thyroid nodules, and can help us take some decisions in the clinical practice, supplementary to fna. nevertheless, the quality of the ultrasound examination depends on the experience of the examiner and on the characteristics of the equipment, so new studies are necessary to evaluate these factors to the current usage of ultrasonographic characteristics in the evaluation diagnostic of thyroid nodules.
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